 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.text.edits;

 import java.util.ArrayList ;
 import java.util.HashMap ;
 import java.util.Iterator ;
 import java.util.List ;
 import java.util.Map ;

 import org.eclipse.core.runtime.Assert;


 /**
  * Copies a tree of text edits. A text edit copier keeps a map
  * between original and new text edits. It can be used to map
  * a copy back to its original edit.
  *
  * @since 3.0
  */
 public final class TextEditCopier {

     private TextEdit fEdit;
     private Map fCopies;

     /**
      * Constructs a new <code>TextEditCopier</code> for the
      * given edit. The actual copy is done by calling <code>
      * perform</code>.
      *
      * @param edit the edit to copy
      *
      * @see #perform()
      */
     public TextEditCopier(TextEdit edit) {
         super();
         Assert.isNotNull(edit);
         fEdit= edit;
         fCopies= new HashMap ();
     }

     /**
      * Performs the actual copying.
      *
      * @return the copy
      */
     public TextEdit perform() {
         TextEdit result= doCopy(fEdit);
         if (result != null) {
             for (Iterator iter= fCopies.keySet().iterator(); iter.hasNext();) {
                 TextEdit edit= (TextEdit)iter.next();
                 edit.postProcessCopy(this);
             }
         }
         return result;
     }

     /**
      * Returns the copy for the original text edit.
      *
      * @param original the original for which the copy
      * is requested
      * @return the copy of the original edit or <code>null</code>
      * if the original isn't managed by this copier
      */
     public TextEdit getCopy(TextEdit original) {
         Assert.isNotNull(original);
         return (TextEdit)fCopies.get(original);
     }

     //---- helper methods --------------------------------------------

     private TextEdit doCopy(TextEdit edit) {
         TextEdit result= edit.doCopy();
         List children= edit.internalGetChildren();
         if (children != null) {
             List newChildren= new ArrayList (children.size());
             for (Iterator iter= children.iterator(); iter.hasNext();) {
                 TextEdit childCopy= doCopy((TextEdit)iter.next());
                 childCopy.internalSetParent(result);
                 newChildren.add(childCopy);
             }
             result.internalSetChildren(newChildren);
         }
         addCopy(edit, result);
         return result;
     }

     private void addCopy(TextEdit original, TextEdit copy) {
         fCopies.put(original, copy);
     }
 }

